In UMTS (Universal Mobile Telecommunication System) TDD (Time Division Duplex) mode, as known from the 3rd Generation Partnership Project, the allocation of resources to users is problematic since there are 3 dimensions in which resource exists—codes, timeslots and frames. It is also likely that different users will be allocated different throughput rates. The problem is exacerbated in packet-switched applications when allocations are made very frequently for short periods of time.
In these circumstances it is important that the system resource space is efficiently filled otherwise overall system throughput will be reduced. In addition, the processing and memory requirements should also be considered.
Previous work has concentrated almost entirely on the much simpler case of circuit-switched applications. Under these circumstances allocations to users exist for long periods of time and do not change, which is very different to the packet-switched case.
However, application of circuit-switched techniques to packet-switched systems has the disadvantage(s) that since users are serviced with variable rates in each frame, different numbers of resource units will be allocated to users in any given frame. Also, since previous allocations may still exist, allocating resources to users correctly is likely to be problematic.
A need therefore exists for resource allocation for variable rate users wherein the abovementioned disadvantage(s) may be alleviated.